Electrosurgical medical system and method

Abstract

A medical device system and method provide an RF electrosurgical generator coupled to an electrosurgical electrode via a patient box disposed in close proximity to the patient. An RF signal is delivered from the generator to the patient box where signal power is increased and the RF signal delivered to the electrosurgical electrode. The patient box is coupled to the electrosurgical electrode by a short cable capable of carrying an HV, high frequency 5 MHz signal without leakage. An electrical characteristic associated with the electrosurgical electrode is monitored and a desired RF power output and duty cycle maintained by adjusting DC input voltage applied to an RF amplifier, responsive to the monitoring. The system determines when the electrosurgical cutting electrode has started cutting and switches from a start mode to a run mode having a different RF duty cycle and a reduced RF power output controlled by a servo system.

1. A system for mitigating leakage in an RF electro surgical generator, comprising:
 an RF electrosurgical generator coupled to a patient box coupled to an electrosurgical electrode, wherein said RF electrosurgical generator is configured to generate an RF signal, said patient box is configured to receive said RF signal from said RF electrosurgical generator, and said patient box is configured to supply an RF output signal to said electrosurgical electrode; 
 a return electrode coupled to said patient box; 
 a balanced and symmetrical shielded transmission line that couples said RF electrosurgical generator disposed in a first housing to said patient box disposed in a second separate housing; 
 a common mode choke disposed in said patient box, said common mode choke including an output winding and a return winding, each of said windings wound about a ferrite core, said output winding and said return winding spaced apart and in parallel to maintain a desired impedance, said output winding comprising a wire carrying said RF output signal and said return winding comprising a duality of intertwined wires carrying a return signal from said return electrode, each of said windings having adjacent ribs spaced apart and each of said windings wound in opposite directions, said common mode choke being configured to receive a common mode signal from said RF output signal and block said common mode signal. 
 
     
     
       2. The system of  claim 1 , further comprising a control circuit and a telemetry circuit arranged in said patient box. 
     
     
       3. The system of  claim 1 , further comprising an operable mechanical input coupled to said RF electrosurgical generator via a fiber optic cable, the mechanical input being configured to send a cut signal and a coagulate signal to said RF electrosurgical generator. 
     
     
       4. The system of  claim 1 , wherein said RF signal has a frequency of about 5 MHz. 
     
     
       5. The system of  claim 1 , wherein said balanced and symmetrical shielded transmission line causes positive and negative portions of said RF signal to cancel.